BBC TV, weirdly and perhaps temporarily, is being let through loud and clear with quite startling and gruesome footage of tanks rolling into Tiananmen Square 20 years ago this evening, plus an interview with one family whose child was shot dead that day, plus with the photographer who took the immortal “tank man” picture.

CNN, on the other hand, goes black-screen for several-minute periods, starting a few seconds after the words “In Beijing twenty years ago…” or “At Tianan….” The censors are just fast enough, or slow enough, to reveal what they are doing — very much like last year, during the violence in Tibet, when you’d see an opening shot of Lhasa followed by black screen.

During my time in Beijing over the past year and a half, I’ve often seen the square itself totally closed off to visitors, as it is at the moment. There are always plenty of security forces around — soldiers in green uniforms, various kinds of police in blue uniforms, and “plainclothes” forces who are pretty easy to pick out, like strapping young men in buzz cuts all wearing similar-looking “leisure” clothes. But I have not seen before anything like the situation at the moment.

There are more representatives in all categories — soldiers, police, obvious plainclothesmen — than I recall seeing even during the Tibet violence in early 2008 or through the Olympic games. Also many people whom you would normally classify as fruit vendors, tourists from the Chinese provinces, youngish white collar workers male and female, and skateboarder-looking characters wearing cargo shorts and with fauxhawk haircuts, were last night walking up and down the sidewalks with their eyes constantly on visitors and drifting up next to people who were holding conversations.

Once “inside” [Tiananmen Square], it looked really weird. There were collections of people in yellow shirts, pink shirts, purple shirts, turquoise shirts. There were more groups holding like-patterned umbrellas. It seemed like everyone had umbrellas, men and women alike. But the Chinese do like umbrellas on sunny days! There were formations of green uniforms marching around; police trucks driving slowly around the edges, an occasional car blustering through (as usual) the crowd. There were lots of solitary undercover police, just like last night. Many wore black, others in their own street clothes.

Lots of groups were obviously deputized young men who stood around watching, staring, following people like me at least 3 on 1 at any given moment. There were no women in this capacity. There was a clear absence of the usual “oblivious” quality of Chinese crowd movement, where people bump into you, brush against you, or cut in front of you if you happen to be in the path of where they’re going. Everyone milling about was acutely aware of everyone else in his space. They seemed to have assigned space. Some deputies also wore group-colored shirts, all wore “badges” with the Chinese flag surrounded in gold, Many looked like the kids who volunteered at the Olympics. Clearly nationalistic. All young. I wondered if they were paid for the day.

I would guess about 85% of people on the square were there officially. You could tell that because the security lines were basically unpopulated, while all the “deputies” just walked around the screeners without being checked. There were very few tourists, foreign or otherwise. There were mostly uniformed and non-uniformed police. Some foreigners were taking pictures, seemingly unmolested. Any footage and photos will be dull-looking; the shots would look “normal”. It was just the feeling of intense orchestration and deliberate crowd-building that gave it away. And also a distinct sense of high-tension, which carried around the front of the Forbidden City, but evaporated just around the corners.